Cognitive decline among older adults with depressive symptoms before and during the COVID-19 pandemic

Background: Whether the COVID-19 pandemic would induce accelerated cognitive decline in individuals with depressive symptoms is undetermined. Objective: To investigate the impact of the COVID-19 pandemic on cognitive function among older adults with depressive symptoms.Methods: Data were from the Health and Retirement Study. The interval between wave 13 and wave 14 was defined as the prepandemic period, and the interval between wave 14 and wave 15 was defined as the pandemic period. Linear mixed models and modified Poisson regression models were employed to compare the differences in cognitive decline and incident dementia between participants with and without depressive symptoms before and during the pandemic.Results: A total of 9304 participants were included. During the prepandemic period, no significant difference was observed in changes in cognitive scores between participants with and without depressive symptoms. During the pandemic period, an accelerated decline in cognitive scores was found between the two groups (global cognition:-0.25, 95 % CI:-0.41 to-0.08, P = 0.004; memory:-0.16, 95 % CI:-0.31 to-0.02, P = 0.030; executive function:-0.08, 95 % CI:-0.15 to-0.02, P = 0.014). Participants with depressive symptoms had a higher risk of developing dementia during the pandemic (RR: 1.48, 95 % CI: 1.17 to 1.88, P < 0.001).Limitations: Causal relationship cannot be concluded due to the observational study design.Conclusions: Older adults with depressive symptoms suffered more severe cognitive deterioration and had a higher risk of incident dementia during the pandemic, underscoring the need to provide cognitive monitoring and interventions for those with depressive symptoms during the COVID-19 pandemic.